I'm making a large batch of poolish starter for a pizza restaurant. If I pour about 4.8 to 5.2 quarts of water into mixer, with about 6 quarts of water, approximately how much yeast should I add? I'm thinking somewhere around 1 tablespoon or possibly less?

I'm making a large batch of poolish starter for a pizza restaurant. If I pour about 4.8 to 5.2 quarts of water into mixer, with about 6 quarts of water, approximately how much yeast should I add? I'm thinking somewhere around 1 tablespoon or possibly less?

Is there something incorrect in the above? Specifically, where it the flour for the poolish?

The first thing I suggest that you do is convert your volume measurement to weights, using a good digital scale with a tare feature. If you are really after a classic poolish, as opposed to some other form of preferment, such as a sponge or biga, then the poolish should constitute equal weights of flour and water, for a hydration of 100%. Then, you should take a look at the Didier Rosada articles at http://web.archive.org/web/20040814193817/cafemeetingplace.com/archives/food3_apr2004.htm and at http://web.archive.org/web/20050829015510/www.cafemeetingplace.com/archives/food4_dec2004.htm.. In the first article, you see a Chart A under the poolish section of the article. That chart sets forth typical yeast quantities to use over three different possible fermentation periods. Keep in mind, however, that the chart is predicated on using fresh yeast and presumes a room temperature of 80-85 degrees F and a water temperature of 60 degrees F. The fresh yeast can be easily converted to dry yeast, such as ADY or IDY, and the water temperature should pose no problem, but you will have to adjust the amount of yeast upwardly if you are to ferment the poolish at your basement temperature of 65-70 degrees F.

Whatever you choose to do, you should note the actual fermentation temperature and you should note when the poolish "breaks", that is, when it peaks and starts to recede. You should note the number of hours that it took to reach that point. That number, along with the fermentation temperature at the time of the pooolish "break", should be usable thereafter to adjust the amount of yeast for the next batch.

If what you intend to use is not actually a poolish, then you might read other sections of the Rosada articles for guidance.